Mechanics

VACUUM LEAK

2004 Ford Escape • 6 cylinder 4WD Automatic • 95,000 miles

2004 Ford Escape, 3.0 V6, 97,000 miles.
. Just replaced the coils and plugs, which as you know involves removing the upper intake manifold. I made sure I was very careful when disconnecting and reconnecting hoses, connectors, etc, as I did not want to end up with a vacuum leak. I put new gaskets in the upper intake manifold, and applied the specified torque to the manifold bolts. After it was all back together, I followed the procedure to relearn the idle and fuel trim strategy, which involves driving the vehicle for at least 10 miles. During that drive, everything seemed fine, no engine light came on.
The next morning, started the vehicle, and the engine light came on. Received the codes "P2195 - O2 sensor stuck lean, bank 1, sensor 1" and "P2197 - O2 sensor stuck lean, bank 2, sensor 1", which is most likely a vacuum leak.
Why would this not occur during the immediate drive right after the repair, but instead the next day? Does this clue any experts out there as to what the problem might be? Any help is truly appreciated.
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Leodajim
March 23, 2011.



Lean fuel condition could be caused by one of the following below: 1. Vacuum leaks
2. EGR and PCV valve.
3. Low fuel pressure.
4. Dirty fuel injectors.
5. Mass Air Flow Sensor.
6. Oxygen Sensor.

Rasmataz
Mar 23, 2011.
The reason it didn't occur until the next day is that the computer was compensating for the lean mixture until it reached it's limits and that's when it set the code. Listen for the hissing noise and try to follow it to it's source.

Wrenchtech
Mar 23, 2011.
Thank you rasmataz and Wrenchtech. I can hear the hissing noise in there, and have been spraying carb cleaner to try and find it, with little change in the idle. The PCV hose yielded a small change in the idle when sprayed, so I will start there, and probably replace the PCV valve while I'm at it since the mileage is so close to 100,000.

Tiny
Leodajim
Mar 24, 2011.
I've found a number of these with the rubber connectors at the manifold with holes sucked through them and sometimes the same thing on the rubber part of the PCV hose.

Wrenchtech
Mar 24, 2011.
I talked to a Ford dealership about replacing the PCV hose from the manifold to the valve, and I've learned that it is actually two separate pieces, which seems kind of illogical for something that cannot have any holes or leaks, and the total cost for both pieces is around $60.
Couldn't I achieve the same result by using a section of 5/8" diameter PCV hose? I would route the hose on the same path that the existing hose uses.

Tiny
Leodajim
Mar 24, 2011.
Not likely. The plastic takes the corners without kinking.

Wrenchtech
Mar 24, 2011.